/* 
 * File:   meter.h
 * Author: torsten.roemer@luniks.net
 *
 * Created on 1. Mai 2023, 23:42
 */

#ifndef METER_H
#define METER_H

/** Use AVCC as reference voltage */
#define AREF_AVCC   (1 << REFS0)
/** Use internal 1.1V reference voltage */
#define AREF_INT    (1 << REFS1) | (1 << REFS0)

#define AREF_MV     1100 // 1136

/** 0°C in Kelvin */
#define TMP_0C      273.15

/** Specifications of the NTC Thermistor 0.1°C */
#define TH_RESI     100000
#define TH_TEMP     298.15
#define TH_BETA     3892
/** Serial resistance */
#define TH_SERI     100000

/** Ratiometric response of the HIH-5030 at 0%RH and 100%RH with 12-bit ADC */
#define RH_ADC_0    620  // Vout = Vsupply * 0.1515
#define RH_ADC_100  3225 // Vout = Vsupply * 0.7875
#define RH_ADC      RH_ADC_100 - RH_ADC_0

/** Battery cutoff voltage in millivolts */
#define BAT_LOW     3000

/** Weight of the exponential weighted moving average as bit shift */
#define EWMA_BS     4

/** Returns the battery voltage in millivolts divided by 5 */
int16_t getMVBat(void);

/**
 * Measures temperature, relative humidity and battery voltage and updates 
 * the average values.
 */
void measureValues(void);

/**
 * Calculates, formats and displays the averaged temperature, relative humidity 
 * and battery voltage values.
 */
void displayValues(void);

#endif /* METER_H */